Mobile phone communications technology has evolved to the third-generation, also referred to as “3G” technology, where network operators can offer users a wider range of more advanced services, including wide area wireless voice telephony and broadband wireless data within a mobile environment. Earlier technologies prior to “3G” (i.e., pre-3G technologies) were limited in that only one voice or data channel could be active at a time. In contrast, “3G” permits parallel and independent use of a voice channel and a data channel, also referred to as Dual-Transfer Mode (DTM).
Efforts also are underway to offer enhanced services to mobile phones using a 3G network. The “enhanced services” refer to enterprise-type telephony services that historically have been offered only to telephony users of a private branch exchange, including calling features such as hold, resume, transfer, conference, single number reach, “park” (i.e., waiting to call back a destination that currently is busy), call forwarding activation and deactivation, etc., and other enterprise-type services for enterprise telephony users such as unified communications. Such enhanced services can be provided to a mobile phone via an existing wireless telephony network (e.g., GSM, CDMA) based on supplying enhanced services signaling data via the wireless telephony network data channel while providing the voice data via the wireless telephony network voice channel.